Condensate extraction system



April 3, 1934. J 5 1,953,835

CONDENSATE EXTRACTION SYSTEM Filed Nov. 7, 1933 2 Sheets-Sheet 1 April 3, 1934. I Sm 1,953,835

CONDENSATE EXTRACTION SYSTEM Filed Nov. 7, 1953 2 Sheets-Sheet 2 @.Zw J0 J5 m H J4- Patented Apr. 3, 1934 stares P A T E i reins James Sim, Catiicart, Glasgow, Scotland, assignor to G. & J. Weir, Limited, Glasgow, Scotland, a corporation of Great Britain and Northern Ireland Application November 7, 1933, Serial No. 697,091 In Great Britain December 28, 1932 5 Claims.

This invention relates to condensate extraction systems of the type including two condensers and two condensate extraction pumps, for installation in ships, and has for an object to obviate drawbacks experienced in the operation of the condensate extraction pumps due to changes in the suction head occasioned by the motion of the ship in a seaway.

As is understood, particularly in fast naval craft, such as torpedo boat destroyers with underhung condensers, the available suction head for the condensate extraction pumps is very limited, so that a problem arises in ensuring that the condensate extraction pumps shall be continuously supplied with condensate in order that in the case of a closed feed system the pressure in the boiler feed suction main may be maintained.

In systems of the type referred to one extraction pump is commonly used to do duty for the two condensers while cruising, and troubles have been met with in practice under this condition do to the condensate water flowing from one condenser to the other as the ship rolls, thus preventing the working extraction pump from being continuously supplied with sufiicient water to maintaln stable conditions in the feed system.

According to the present invention, a condensate extraction system of the type referred to incorporates a cross-connection or connections between the conduits connecting the condensate outlets of the condensers with the pumps, and non-return valves for preventing the flow of condensate from one condenser to the other, thus ensuring that the suction head for either pump when working alone shall be maintained above the minimum.

In the accompanying drawings Fig. 1 is a part plan part horizontal section showing one embodiment of the invention, Figs. 1 and 1 are a vertical section and a plan view with top plate omitted, respectively, showing a non-return valve with a dashpot device, Figs. 2 and 3 are a plan and an elevation, respectively, showing a modified construction.

Referring to Fig. 1, 1, 2 denote port and starboard condensers which are served by condensate extraction pumps 3, 4.

The suction branch or" the pump 3 is connected to the condensate outlet 5 of the condenser 1 by way of a pipe 6, non-return valve 7, T-piece 8, and shut-off valve 9.

The suction branch of the pump 4 is connected to the condensate outlet of the condenser 2 by way of pipe and valve fittings 11--14: corresponding respectively, to the pipe and valve fittings 6-9.

A cross pipe connection 15 in which is interposed an isolating valve 16 extends between the T-pieces 8 and 13, i. e., downstream of the nonreturn valves 7, 12.

The discharge branches of the pumps 3, i are fitted with shut-off valves 18, 19, and are joined to a common discharge pipe 17.

The non-return valves 7, 12 comprise semibalanced butterfly valve elements 20, 21, respectively, pivoted ofi-centre on vertical spindles 22, 23 within their respective valve chests. The valve elements 20, 21 when in open position present the minimum resistance to flow of condensate to the pumps, and are adapted to shut automatically on initiation of reflux flow.

To prevent slamming of the non-return valve elements 2b, 21, each of the spindles 22, 23 of said valve elements is operatively connected to a dashpot device (Figs. 1 and l including a paddle secured on the respective valve spindle and fitted for oscillatory movement within a sectoral chamber 31 having a valve-contro1led by-pass pipe 32 interconnecting the two compartments separated by the paddle 30 within the chamber 31 which is kept drowned with water supplied thereto by way of a pipe-connection 33. As will be understood, by adjusting the by-pass control valve 34 to regulate the flow of water from one side of the paddle to the other, side of the paddle, the requisite damping of the movement of the non-return valve is obtained.

When both pumps 3, 4-. are working, the shut-off valves 9, 14 are open and the isolating valve 16 shut, so that the pumps draw from their respective condensers, the non-return valve elements 20, 21 retaining their full open position as shown.

In these conditions rolling of the ship has little or no effect on the suction head over the pumps 3, 4, and no trouble is experienced.

When the ship is cruising and the pump 3 only is working, the valve 14 is shut and the valves 9, 16 are open. During a roll to port condensate from the starboard condenser 2 flowing through the pipe 15 initiates reflux flow past the valve element 20 which thereupon shuts, so that, while condensate from the port condenser 1 accumulates upstream of the valve element 20, the pump 3 draws from the condenser 2. During a roll to starboard the valve element 20 opens and condensate from the port condenser 1 flows through the pipe 15 and shuts the valve element 21, so that, while condensate from the starboard condenser 2 accumulates upstream oi": the valve element 21, the pump 3 draws from the condenser 1.

The modified arrangement shown in Figs. 2 and 3 includes cross pipe connections 24, 25 fitted with screw-down non-return valves 26, 27, respectively, and coupled to T-pieces 28, 29 joined to the suction branches of the pumps 3, 4.

When both pumps 3, 4 are working, the valves 26, 2? are shut down and the pumps deal in normal manner with the condensate from the respective condensers 1, 2.

When the pump 3 only is working, the valve 27 is shut down and the valve 26 is free to function as a non-return valve. During a roll to port condensate from the starboard condenser 2 flows through the pipe 24 and valve 26, and is drawn into the pump 3 before it can pass back to the port condenser 1. During a roll to starboard fiow of condensate from the port condenser 1 to the starboard condenser 2 is prevented by the automatic closing of the valve 26.

Conversely, if the pump 4 is the working pump, the valve 26 is shut down and the valve 27 is free to function as a non-return valve.

As will be understood, the arrangement is such that, under cruising conditions normally requiring only the working of one condensate extraction pump, the suction head of said pump is maintained above the minimum irrespective of any rolling motion of the ship.

What I claim is:--

1. A condensate extraction system including two condensers having condensate outlets, two condensate extraction pumps having suction branches, conduits connecting said condensate outlets with said suction branches, at least one cross-connection between said conduits, and nonreturn valves for preventing flow of condensate from one condenser to the other.

2. A condensate extraction system as claimed in claim 1 in which the non-return valves are fitted in the conduits upstream of the cross-connection, and are arranged when open to permit substantially unrestricted flow of condensate towards the pumps but are adapted to shut automatically on initiation of reflux flow.

3. A condensate extraction system as claimed in claim 1 in which the non-return valves comprise butterfiy valve elements pivoted off-centre on vertical axes.

4. A condensate extraction system as claimed in claim 1 including dashpot devices for preventing slamming of the non-return valves.

5. A condensate extraction system as claimed in claim 1 the non-return valves being two nonreturn valves of the screw-down type interposed one in each of two cross connections.

JAMES SIM. 

